Seawater softening of suture zones inhibits fracture propagation in Antarctic ice shelves
| Autor: | Suzanne Bevan, Adam Booth, Daniel McGrath, Sarah Thompson, Adrian Luckman, Daniela Jansen, Bernd Kulessa, Edward C. King, Paul R. Holland, Martin O'Leary, Bryn Hubbard |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Cryospheric science Provenance 010504 meteorology & atmospheric sciences Science General Physics and Astronomy 01 natural sciences Fracture propagation General Biochemistry Genetics and Molecular Biology Ice shelf Article 03 medical and health sciences Climate change 14. Life underwater Suture (geology) Petrology lcsh:Science Softening Stress intensity factor 0105 earth and related environmental sciences geography Multidisciplinary geography.geographical_feature_category Micro cracks General Chemistry 030104 developmental biology Seawater lcsh:Q human activities Geology |
| Zdroj: | Nature Communications Nature Communications, Vol 10, Iss 1, Pp 1-12 (2019) |
| ISSN: | 2041-1723 |
| Popis: | Suture zones are abundant on Antarctic ice shelves and widely observed to impede fracture propagation, greatly enhancing ice-shelf stability. Using seismic and radar observations on the Larsen C Ice Shelf of the Antarctic Peninsula, we confirm that such zones are highly heterogeneous, consisting of multiple meteoric and marine ice bodies of diverse provenance fused together. Here we demonstrate that fracture detainment is predominantly controlled by enhanced seawater content in suture zones, rather than by enhanced temperature as previously thought. We show that interstitial seawater can reduce fracture-driving stress by orders of magnitude, promoting both viscous relaxation and the development of micro cracks, the incidence of which scales inversely with stress intensity. We show how simple analysis of viscous buckles in ice-penetrating radar data can quantify the seawater content of suture zones and their modification of the ice-shelf’s stress regime. By limiting fracture, enhancing stability and restraining continental ice discharge into the ocean, suture zones act as vital regulators of Antarctic mass balance. Suture zones are abundant on Antarctic ice shelves and widely observed to impede fracture propagation. Here we show that fracture detainment is principally controlled by the zones’ enhanced seawater contents, reducing fracture-driving stresses by orders of magnitude and therefore greatly enhancing stability. |
| Databáze: | OpenAIRE |
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